Study of elliptical annular microstrip antenna using full Mathieu formulation

Elliptical annular microstrip antennas with arbitrary eccentricity are studied using the full Mathieu formulation. The feed point is arbitrarily placed on the elliptical annular shaped patch. The study includes the computation of internal field, radiation field, circular polarization, input impedance, and slot admittance, required to formalize the radiation mechanism, for both inner and outer radiating edges. The calculated results show that the slot conductances of the inner and outer radiating edges have different frequency dependences. Circular polarization can be obtained if the feed point is along the radial line of 45/spl deg/. The position of the feed point has a strong effect on the radiating field, slot conductance, and input impedance.<>